North Korea says it has sentenced an American citizen to 15 years of hard labor after finding him guilty of committing what it says are "hostile acts" against the state.

The official Korean Central News Agency said Thursday that Pae Jun-ho, known as Kenneth Bae in the United States, was convicted at a trial two days earlier. It has previously said he confessed to committing crimes aimed at toppling the government.

The 44-year-old was arrested in November in the northeastern port city of Rason, which lies in a special economic zone near the border with Russia and China.

Various media reports have described Bae as a Korean-American tour operator, and said he was arrested for carrying a computer that contained sensitive or controversial information.

The North Korean announcement comes at a time of increased tensions on the Korean peninsula. In recent weeks, Pyongyang has threatened attacks against South Korea and the U.S. in response to expanded sanctions against its latest nuclear test.

North Korea has detained several Americans in recent years, mostly journalists or Christians accused of proselytizing.

In 2009, two television journalists were detained and sentenced to 12 years of hard labor after crossing into the North from China. Former U.S. President Bill Clinton later traveled to North Korea to win their release.

In 2010, former U.S. President Jimmy Carter negotiated the release of U.S. national Aijalon Mahli Gomes, who was sentenced to eight years of hard labor.